External lens adapted to change refractive properties

ABSTRACT

A lens system is provided. The lens system includes a lens adapted to be positioned along the main optical axis of the eye and a control unit. The control unit is operable with the lens to alter the focal length of the lens based at least partly upon a condition, such that the lens alters light rays and focuses the rays on the retina of the eye.

This application is a continuation-in-part of application Ser. No.11/259,781, now abandoned, entitled “Intraocular Lens Adapted forAccommodation Via Electrical Signals”, filed Oct. 27, 2005, the entirecontents of which are hereby incorporated by reference.

BACKGROUND

A normal emetropic eye includes a cornea, lens and retina. The corneaand lens of a normal eye cooperatively focus light entering the eye froma far point, i.e., infinity, onto the retina. However, an eye can have adisorder known as ametropia, which is the inability of the lens andcornea to focus the far point correctly on the retina. Typical types ofametropia are myopia, hypermetropia or hyperopia, and astigmatism.

A myopic eye has either an axial length that is longer than that of anormal emetropic eye, or a cornea or lens having a refractive powerstronger than that of the cornea and lens of an emetropic eye. Thisstronger refractive power causes the far point to be projected in frontof the retina.

Conversely, a hypermetropic or hyperopic eye has an axial length shorterthan that of a normal emetropic eye, or a lens or cornea having arefractive power less than that of a lens and cornea of an emetropiceye. This lesser refractive power causes the far point to be focused inback of the retina.

An eye suffering from astigmatism has a defect in the lens or shape ofthe cornea. Therefore, an astigmatic eye is incapable of sharplyfocusing images on the retina.

An eye can also suffer from presbyopia. Presbyopia is the inability ofthe eye to focus sharply on nearby objects, resulting from loss ofelasticity of the crystalline lens.

Optical methods are known which involve the placement of lenses in frontof the eye, for example, in the form of glasses or contact lenses, tocorrect vision disorders. A common method of correcting myopia is toplace a “minus” or concave lens in front of the eye in order to decreasethe refractive power of the cornea and lens. In a similar manner,hypermetropic or hyperopic conditions can be corrected to a certaindegree by placing a “plus” or convex lens in front of the eye toincrease the refractive power of the cornea and lens. Lenses havingother shapes can be used to correct astigmatism. Bifocal lenses can beused to correct presbyopia. The concave, convex or other shaped lensesare typically configured in the form of glasses or contact lenses.

SUMMARY

In one embodiment, a lens system is provided. The lens system includes alens adapted to be positioned along the main optical axis of the eye anda control unit. The control unit is operable with the lens to alter thefocal length of the lens based at least partly upon a condition, suchthat the lens alters light rays and focuses the rays on the retina ofthe eye.

In another embodiment, a lens is provided. The lens includes a chamberadapted to house a substance. The lens is adapted to be positionedexternally and relative to an eye and coupled to a control unit. Thecontrol unit is operable to control the focal length of the lens byinfluencing the substance, such control of the focal length alteringlight rays and focusing the light rays on the retina of the eye.

In another embodiment, a control unit is provided. The control unitincludes an electronic circuit. The control unit is coupled to a lens,which includes a chamber adapted to house a substance. The lens isadapted to be positioned externally and relative to an eye. Theelectronic circuit is operable to control the focal length of the lens,such control of the focal length altering light rays and focusing thelight rays on the retina of the eye.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side elevational view in section taken through the center ofan eye showing the cornea, pupil, crystalline lens, and capsular bag.

FIG. 2 is a side elevational view in section of the eye shown in FIG. 1showing the capsular bag after removal of the crystalline lens.

FIG. 3 is a side elevational view in section of the eye shown in FIG. 2showing the treatment of the interior of the capsular bag with a liquidto prevent capsular opacification.

FIG. 4 is a side elevational view in section of the eye shown in FIG. 3showing placement of a replacement lens into the capsular bag.

FIG. 5 is a side elevational view in section of the eye shown in FIG. 3in which a replacement lens is positioned in the capsular bag and afluidic system and remote power unit are positioned in the posteriorchamber.

FIG. 6 is a flow chart of the process of accommodation in accordancewith one embodiment of the present invention.

FIG. 7 is a flow chart of the process of accommodation in which thefluidic system includes a pressure sensor for sensing the pressure in atleast one of the chambers in accordance with one embodiment of thepresent invention.

FIG. 8 is a side elevational view in section of the eye shown in FIG. 3in which a replacement lens is positioned in the capsular bag and apower unit is positioned in the posterior chamber.

FIG. 9 is a flow chart of the process of accommodation in response toelectrical signals in accordance with one embodiment of the presentinvention.

FIG. 10 is a side view in section of another embodiment of the presentinvention, showing the adjustable lens positioned relative to the eye.

FIG. 11 is a side view in section of another embodiment of the presentinvention, showing the adjustable lens as a contact lens.

DETAILED DESCRIPTION

In various embodiments, a lens capable of accommodation in response toelectrical signals is provided. The lens can be placed at any suitablelocation along the optical path of an eye, including but not limited towithin the capsular bag, in place of the capsular bag, within theposterior chamber or on, in or behind the cornea. Further, it should benoted that any suitable section of the capsular bag can be removed,including but not limited to an anterior portion or a posterior portionaround the main optical axis of the eye. The lens is preferably coupledto a fluidic pumping system which is also coupled to a control systemwhich preferably includes a power source and a signal generation unit.

Referring initially to FIG. 1, a normal eye 10 has a cornea 12, an iris14, and a crystalline lens 16. The crystalline lens 16 is containedwithin a capsular bag 18 that is supported by zonules 20. The zonules20, in turn, are connected to the ciliary muscle 22. According toHelmholz's theory of accommodation, upon contraction of the ciliarymuscle 22, the tension on the zonules 20 is released. The elasticity ofthe lens causes the curvature of the lens 16 to increase, therebyproviding increased refractive power for near vision. Conversely, duringdis-accommodation, the ciliary muscle 22 is relaxed, increasing thetension on the zonules 20 and flattening the lens 16 to provide theproper refractive power for far vision.

If the electrically accommodating lens is to be positioned within thecapsular bag and, thus, replace the crystalline lens, a suitable firststep is to remove the existing lens. As illustrated in FIG. 2, the lensis preferably removed using any technique which allows removal of thelens through a relatively small incision, preferably about a 1-2 mmincision. The preferred method is to create a relatively small incision24 in the cornea 12 and then perform a capsulorhexis to create anopening 26 into the anterior side 28 of the capsular bag 18. Anultrasonic probe 30 is inserted into the capsular bag 18 through theopening 26. The probe's vibrating tip 32 emulsifies the lens 16 intotiny fragments that are suctioned out of the capsular bag by anattachment on the probe tip (not shown). Alternatively, the lensectomymay be performed by laser phacoemulsification or irrigation andaspiration.

Once the crystalline lens 16 has been removed, the capsular bag 18 canbe treated to help prevent a phenomenon known as capsular opacification.Capsular opacification is caused by the proliferated growth of theepithelial cells on the lens capsule. This growth can result in thecells covering all or a substantial portion of the front and rearsurfaces of the lens capsule, which can cause the lens capsule to becomecloudy and thus adversely affect the patient's vision. These cells canbe removed by known techniques, such as by scraping away the epithelialcells; however, it is often difficult to remove all of the unwantedcells. Furthermore, after time, the unwanted cells typically grow back,requiring further surgery. To prevent capsular opacification, thecapsular bag 18 is preferably treated to eliminate the proliferatedgrowth of epithelial cells, as described below.

As seen in FIG. 3, one method of treating the epithelial cells toprevent capsular opacification is to use a cannula 34 to introduce awarm liquid 36 (preferably about <60° C.) into the capsular bag 18,filling the capsular bag 18. The liquid contains a suitable chemicalthat kills the remaining lens cells in the capsular bag and also cleansthe interior of the capsular bag. Suitable chemicals, as well as othersuitable methods of treatment that prevent capsular opacification aredisclosed in U.S. Pat. No. 6,673,067 to Peyman, which is hereinincorporated by reference in its entirety.

As shown in FIG. 4, a replacement lens 38 is then positioned within thecapsular bag 18. Preferably, the lens 38 can be folded or rolled andinserted through the incision in the capsular bag 18; however, the lens38 can be rigid and/or can be inserted through a larger second incisionin the capsular bag 18 or the initial incision, possibly after theinitial incision is widened, or in any other suitable manner. Preferablythe lens 38 varies its focal length in response to changes in fluidicpressure within the lens made in accordance with electrical signals;however the lens 38 can change its index of refraction or alter itsfocal length in any other suitable manner. Since the capsular bag 18 isstill in place, the capsular bag can still assist in accommodation;however, it is not necessary for capsular bag 18 to assist withaccommodation. The lens, as shown in FIG. 5, preferably includes twochambers 40 set on opposite sides of a substrate 42 and covered with aflexible membrane 44; however, the lens can have one or any othersuitable number of chambers. Preferably, the two chambers 40 contain afluid 46, and preferably the fluid 46 is a sodium chromate solution;however, if desired, one or more of the chambers can contain somethingother than a fluid or the chambers can contain different fluids ordifferent sodium chromate solutions. The substrate 42 is preferablyglass; however, the substrate 42 can be any suitable material.Preferably, the flexible membrane 44 is a biocompatible material;however, the flexible membrane can be any suitable material.

Preferably, the fluidic pressure within the chambers 40 can be alteredusing a fluidic system 48 which includes a miniature fluidic pressuregenerator (e.g., a pump or any other suitable device), a fluid flowcontrol device (e.g., a valve or any other suitable device), a controlcircuit and a pressure sensor; however, the fluidic pressure can bealtered in any suitable manner. Further, if desired, a fluidic system 48does not need a pressure sensor. When subjected to electrical signal,the electronic control circuit of the fluidic system 48 controls thevalves and pumps to adjust the fluidic pressure in one or more of thechambers 40. Preferably, the fluidic pressure is adjusted by pumpingfluid in or releasing a valve to allow fluid to flow out and back intothe system 48; however, the fluidic pressure can be adjusted by pumpingfluid out or in any other suitable manner. As a result, the shape andthe focal length of the lens 38 is altered, providing accommodation.Lenses that similarly change focal length in response to fluidicpressure changes made in accordance with electrical signals aredescribed in greater detail in “Integrated Fluidic Adaptive Zoom Lens”,Optics Letters, Vol. 29, Issue 24, 2855-2857, December 2004, the entirecontents of which is hereby incorporated by reference.

As shown in FIG. 5, fluidic system 48 is preferably positioned in theposterior chamber 50; however, the fluidic system 48 can be positionedoutside the eye, within the sclera, between the sclera and the choroidsor any other suitable location. Further, the fluidic system 48 ispreferably positioned such that it is not in the visual pathway. A tube52 fluidly connects the lens 38 and the fluidic system 48. Preferably,the tube 52 passes through a small incision in the capsular bag 18 nearthe connection of the zonules 20 and the capsular bag 18; however, thetube 52 can pass through the capsular bag in any suitable location.

Preferably, fluidic system 48 includes a power source which ispreferably rechargeable through induction or other suitable means suchas generating and storing electrical energy using eye and/or headmovement to provide the energy to drive the generator; however, fluidicsystem 48 can be connected to a remote power source 54 as shown in FIG.5 or to any other suitable power source. Preferably, the remote powersource 54 is located in the posterior chamber 50; however, the remotepower source 54 can be positioned outside the eye (e.g., under thescalp, within a sinus cavity, under the cheek, in the torso or in anyother suitable location), within the sclera, between the sclera and thechoroids or any other suitable location. Further, the remote powersource 54 is preferably positioned such that it is not in the visualpathway. The remote power source 54 is preferably electrically coupledto the fluidic system 48 by electrically conductive line 56; however,the remote power source 54 can be coupled to the fluidic system 48 inany suitable manner. Further, the remote power source 54 preferablyincludes a signal generator which can supply control signals to thefluidic system 48 via electrically conductive line 56; however, theremote power source 54 can be without a signal generator, if desired, orcan supply control signals to the fluidic system 48 in any suitablemanner. Similar remote power sources are described in more detail inU.S. Pat. No. 6,947,782 to Schulman et al., which is herein incorporatedby reference in its entirety.

Preferably, the remote power source 54 is coupled to a sensor 58 byelectrically conductive line 60; however, the remote power source 54 canbe coupled to sensor 58 in any suitable manner. The sensor 58 ispreferably a tension sensor positioned on the zonules 20 so that thesensor 58 detects the amount of tension present in the zonules 20;however, the sensor 58 can be a wireless signal sensor, aneurotransmitter sensor, a chemical sensor, a pressure sensor or anyother suitable sensor type and/or can be positioned in or near theciliary muscle 22, at or near the nerve controlling the ciliary muscle22, in the capsular bag 18 or in any other suitable location.Preferably, the sensor 58 detects the eye's attempt to cause its lens toaccommodate; however, the sensor 58 can detect a manual attempt toaccommodate the lens 38 (e.g., input through a wireless controller) orany other suitable input. The information detected at the sensor 58 isrelayed to the remote power source 54 via line 60, and the signalgenerator of the remote power source 54 generates a signal in accordancewith the information. The signal is sent to the fluidic system 48, whichadjusts the fluidic pressure in one or more of the chambers 40accordingly. Thus, the eye's natural attempts to focus will result inaccommodation of lens 38. Response of lens 38 may vary from that of thenatural lens; however, the neural systems which control the ciliarymuscle 22 (and therefore the tension on the zonules 20), are providedwith feedback from the optic nerve and visual neural pathways. As aresult, the neural system can learn and adjust to the characteristics ofthe lens 38.

The process of accommodation in accordance with one embodiment is shownin FIG. 6. At step 600, the eye attempts to refocus at a differentdistance, and thus changes the tension on the zonules. At step 610, atension sensor detects the new tension level and relays the informationto a control unit. The control unit preferably includes a remote powersource and a fluidic system; however, the control unit can include anysuitable devices. At step 620, the control unit determines the correctadjustment to be made to the fluidic pressure in at least one chamber ofa fluidic lens in response to the tension sensor information. At step630, the control unit makes the determined fluidic pressure adjustmentand the process repeats at step 600.

Another process of accommodation in accordance with another embodimentin which the fluidic system includes a pressure sensor for sensing thepressure in at least one of the chambers is shown in FIG. 7. At step700, a user sends a signal to refocus his or her eye at a differentdistance. Preferably, the signal is sent wirelessly; however, the signalcan be sent in any suitable manner. Further, the signal preferablyincludes information corresponding to the desired different distance;however, the signal can include information indicating only that thedesired distance is closer or farther or any other suitable information.At step 710, a sensor detects the signal and relays the information to acontrol unit. The control unit preferably includes a remote power sourceand a fluidic system; however, the control unit can include any suitabledevices. At step 720, the control unit determines a new fluidic pressurelevel to be created in at least one chamber of a fluidic lens inresponse to the sensor information. At step 730, the control unitincreases or decreases, as appropriate given the current fluidicpressure as determined by the pressure sensor, the fluidic pressure inthe chamber. At step 740 it is determined whether the desired fluidicpressure is equal to the pressure sensed by the pressure sensor. If thedesired fluidic pressure is equal to the pressure sensed by the pressuresensor, at step 750, the lens is accommodated and the process repeats atstep 700. If the desired fluidic pressure is not equal to the pressuresensed by the pressure sensor, the process repeats at step 730.

FIG. 8 illustrates an alternative accommodating lens 62. Lens 62responds to electrical stimulation by changing its focal length. Similarto lens 38, lens 62 is preferably placed within the capsular bag 18;however, the lens 62 can be placed in the posterior chamber 50, in placeof the capsular bag 18, within the cornea 12, on the surface of the eyeor in any other suitable location. Further, it should be noted that anysuitable section of the capsular bag can be removed, including but notlimited to an anterior portion or a posterior portion around the mainoptical axis of the eye. If the lens 62 is placed within the capsularbag 18, the capsular bag can assist with accommodation; however, it isnot necessary for the capsular bag 18 to assist with accommodation. Lens62 may have one or more chambers that are at least partly filled with afluid or other substance; however, lens 62 is not required to have achamber.

Preferably, lens 62 is a fluid lens that alters its focal length bychanging its shape; however lens 62 can be any suitable type of lens andcan change its focal length in any suitable manner. The lens 62preferably includes two immiscible (i.e., non-mixing) fluids ofdifferent refractive index (or other suitable optical property);however, the lens 62 is not required to include two immiscible fluids ofdifferent refractive index. Preferably, one of the immiscible fluids isan electrically conducting aqueous solution and the other anelectrically non-conducting oil, contained in a short tube withtransparent end caps; however, the immiscible fluids can be any suitablefluids and can be contained in any suitable container. The internalsurfaces of the tube wall and one of its end caps are preferably coatedwith a hydrophobic coating that causes the aqueous solution to formitself into a hemispherical mass at the opposite end of the tube, whereit acts as a spherically curved lens; however, the hydrophobic coatingis not required and, if present, can be arranged in any suitable manner.Further, the coating can include any suitable material, includinghydrophilic substances.

Preferably, the shape of the lens 62 can be adjusted by applying anelectric field across the hydrophobic coating such that it becomes lesshydrophobic (a process called “electrowetting” that results from anelectrically induced change in surface-tension); however, the shape ofthe lens 62 can be adjusted by applying an electric field across anysuitable portion of the lens 62. Preferably, as a result of this changein surface-tension, the aqueous solution begins to wet the sidewalls ofthe tube, altering the radius of curvature of the meniscus between thetwo fluids and hence the focal length of the lens. Increasing theapplied electric field can preferably cause the surface of the initiallyconvex lens to become less convex, substantially flat or concave;however increasing the applied electric field can cause the surface ofthe lens to change in any suitable manner. Preferably, decreasing theapplied electric field has the opposite effect, enabling the lens 62 totransition smoothly from being convergent to divergent, or vice versa,and back again repeatably.

The lens 62 can measure 3 mm in diameter by 2.2 mm in length; howeverthe lens 62 can have any suitable dimensions. The focal range of thelens 62 can be any suitable range and can extend to infinity. Further,switching over the full focal range can occur in less than 10 ms or anyother suitable amount of time. Preferably, lens 62 is controlled by a DCvoltage and presents a capacitive load; however, the lens 62 can becontrolled by any suitable voltage and operate with any suitableelectrical properties.

Lens 62 is electrically coupled to a power source 64 by electricallyconductive line 66; however, lens 62 can be coupled to power source 64in any suitable manner. Preferably, power source 64 is rechargeablethrough induction or other suitable means such as generating and storingelectrical energy using eye and/or head movement to provide the energyto drive the generator; however, the power source 64 can benon-rechargeable, if desired. Similar to remote power source 54, thepower source 64 is preferably located in the posterior chamber 50;however, the power source 64 can be positioned outside the eye (e.g.,under the scalp, within a sinus cavity, under the cheek, in the torso orin any other suitable location), within the sclera, between the scleraand the choroids or any other suitable location. Further, the powersource 64 is preferably positioned such that it is not in the visualpathway. The power source 64 preferably includes a signal generatorwhich can supply current to the lens 62 via electrically conductive line66; however, the power source 64 can be without a signal generator, ifdesired, or can supply control signals to the lens 62 in any suitablemanner.

Preferably, the power source 64 is coupled to a sensor 68 byelectrically conductive line 70; however, the power source 64 can becoupled to sensor 68 in any suitable manner. The sensor 68 is preferablya tension sensor positioned on the zonules 20 so that the sensor 68detects the amount of tension present in the zonules 20; however, thesensor 68 can be a wireless signal sensor, a neurotransmitter sensor, achemical sensor, a pressure sensor or any other suitable sensor typeand/or can be positioned in or near the ciliary muscle 22, at or nearthe nerve controlling the ciliary muscle 22, in the capsular bag 18 orin any other suitable location. Preferably, the sensor 68 detects theeye's attempt to cause its lens to accommodate; however, the sensor 68can detect a manual attempt to accommodate the lens 62 (e.g., inputthrough a wireless controller) or any other suitable input. Theinformation detected at the sensor 68 is relayed to the power source 64via line 70, and the signal generator of the power source 64 generates asignal in accordance with the information. The signal is sent and passedthrough the lens 62, which preferably changes shape as a result of theelectrical current flowing through it; however, the lens 62 could changeits index of refraction in response to the electrical current flowingthrough it or change its focal length in any other suitable manner.Preferably, line 70 includes two separate electrical pathways thatelectrically couple to lens 62 at different, preferably substantiallyopposite, locations so that one of the pathways can serve as a groundwire; however, the lens 62 can be grounded in any other suitable mannerto enable current supplied via line 70 to flow through the lens 62. As aresult, similar to lens 38, the eye's natural attempts to focus willresult in accommodation of lens 62. Response of lens 62 may vary fromthat of the natural lens; however, as with lens 38, the neural systemswhich control the ciliary muscle 22 (and therefore the tension on thezonules 20), are provided with feedback from the optic nerve and visualneural pathways. As a result, the neural system can learn and adjust tothe characteristics of the lens 62.

The process of accommodation in response to electrical signals inaccordance with one embodiment is shown in FIG. 9. At step 900, the eyeattempts to refocus at a different distance, and thus changes thetension on the zonules. At step 910, a tension sensor detects the newtension level and relays the information to a control unit. The controlunit preferably includes a power source; however, the control unit caninclude any suitable devices. At step 920, the control unit determinesthe correct adjustment to be made to the current being passed throughthe lens in response to the tension sensor information. At step 930, thecontrol unit adjusts the current being passed through the lens and theprocess repeats at step 900.

In another embodiment, as illustrated in FIGS. 10-11, the presentinvention can be used in an external lens. For example, the lens can beconfigured to be used with spectacles (FIG. 10) or as a contact lens(FIG. 11). The embodiments of FIGS. 10-11 are configured to correctrefractive errors in the eye. For example, the present embodiments cancorrect at least myopia (i.e., be a negative diopter lens), hyperopiaand astigmatism. Furthermore, since these embodiments (as discussed inmore detail below) can have their refractive properties altered, theyare multi-focal lenses. Thus, these lenses can correct, among otherdisorders, presbyopia, or any combination of disorders.

When configured to be used in conjunction with spectacles 1000, lens1002 is preferably coupled to a frame 1004 that positions the lens 1002relative to the cornea 1006 of the eye in any suitable manner. As withprevious embodiments, the lens 1002 has a chamber or area 1008 (ormultiple chambers or areas, if desired) that is configured to hold afluid or a mixture of fluids or any other suitable substance. Chamber1008 preferably includes two immiscible (i.e., non-mixing) fluids ofdifferent refractive index (or other suitable optical property);however, the chamber 1008 is not required to include two immisciblefluids of different refractive index. Preferably, one of the immisciblefluids is an electrically conducting aqueous solution and the other anelectrically non-conducting oil, contained in a short tube withtransparent end caps, as described above; however, the immiscible fluidscan be any suitable fluids and can be contained in any suitablecontainer. The above description of the fluids is applicable to thepresent invention.

Preferably, as with the embodiments above, the shape of the lens 1002can be adjusted by applying an electric field across the hydrophobiccoating such that it becomes less hydrophobic (a process called“electrowetting” that results from an electrically induced change insurface-tension); however, the shape of the lens 1002 can be adjusted byapplying an electric field across any suitable portion of the lens 1002.Preferably, as a result of this change in surface-tension, the aqueoussolution begins to wet the sidewalls of the tube, altering the radius ofcurvature of the meniscus between the two fluids and hence the focallength of the lens. Increasing the applied electric field can preferablycause the surface of the initially convex lens to become less convex,substantially flat or concave; however increasing the applied electricfield can cause the surface of the lens to change in any suitablemanner. Preferably, decreasing the applied electric field has theopposite effect, enabling the lens 1002 to transition smoothly frombeing convergent to divergent, or vice versa, and back again repeatably.Thus, allowing the lens 1002 to repeatably focus on near and/or farobjects.

The focal range of the lens 1002 can be any suitable range and canextend to infinity. Further, switching over the full focal range canoccur in less than 10 ms or any other suitable amount of time.Preferably, lens 1002 is controlled by a DC voltage and presents acapacitive load; however, the lens 1002 can be controlled by anysuitable voltage and operate with any suitable electrical properties.

Lens 1002 is electrically coupled to a power source 1010 by electricallyconductive line 1012; however, lens 1002 can be coupled to power source1010 in any suitable manner. Preferably, power source 1010 isrechargeable through direct electrical current, induction or othersuitable means such as generating and storing electrical energy usingeye and/or head movement to provide the energy to drive the generator;however, the power source 1010 can be non-rechargeable, if desired.Power source 1010 is preferably located on the frame 1004 of spectacles1000; however, the power source 1010 can be positioned in any suitablelocation. The power source 1010 preferably includes a signal generatorwhich can supply current to the lens 1002 via electrically conductiveline 1112; however, the power source 1010 can be without a signalgenerator, if desired, or can supply control signals to the lens 1002 inany suitable manner.

Preferably, the power source 1010 is coupled to a sensor 1114 byelectrically conductive line 1116; however, the power source 1010 can becoupled to sensor 1116 in any suitable manner (e.g. wirelessly). Thesensor 1114 is preferably a distance sensor positioned on the front 1118of frame 1004 so that the sensor 1114 detects the distance of an objectaway from the eye (such as a laser range finder); however, the sensor1114 can be any suitable sensor type. Preferably, the sensor 1114 ispositioned relative to the eye such that it detects the distance aspecific object is from the eye and adjusts the lens 1002 accordingly;however, the sensor 1114 can detect a manual attempt to adjust the lens1002 (e.g., input through a wireless controller or direct push buttons)or any other suitable input. The information detected at the sensor 1114is relayed to the power source 1010 via line 1116, and the signalgenerator of the power source 1010 generates a signal in accordance withthe information. The signal is sent and passed through the lens 1002,which preferably changes shape as a result of the electrical currentflowing through it; however, the lens 1002 could change its index ofrefraction in response to the electrical current flowing through it orchange its focal length in any other suitable manner. Preferably, line1116 includes two separate electrical pathways that electrically coupleto lens 1102 at different, preferably substantially opposite, locationsso that one of the pathways can serve as a ground wire; however, thelens 1002 can be grounded in any other suitable manner to enable currentsupplied via line 1116 to flow through the lens 1002.

Additionally, the lens 1002 can be wirelessly coupled to a sensor, suchas sensor 64, described above and adjust based on signals from thecilliary muscles and/or the zonules. Response of lens 1002 may vary fromthat of the natural lens; however, as with lenses described above, theneural systems which control the ciliary muscle 22 (and therefore thetension on the zonules 20), are provided with feedback from the opticnerve and visual neural pathways. As a result, the neural system canlearn and adjust to the characteristics of the lens 1002.

FIG. 11 illustrates another embodiment of the present invention, wherethe lens 1102 is a contact lens that is positioned on the externalsurface 1104 of the cornea 1105.

As with lens 1002, lens 1102 includes a chamber or area 1106 (ormultiple chambers or areas, if desired) having a fluid 1108 therein.Prefereably, fluid 1108 is the same as the fluid described above forlens 1002 and operates in the substantially the same manner; however,any suitable fluid and/or substance or combination thereof can be used.

As described above, lens 1102 is coupled to a power source 1110 via anelectrical wire 1112, or by any other suitable means. The power source1110 is coupled to lens 1102 in any suitable manner (e.g., attached to aprotrusion 1111). Power source 1110 and electrical wire 1112 areconfigured and operate in substantially the same manner as describedabove for lens 1002. Any description of lens 1002 and power source 1010is applicable to lens 1102 and power source 1110.

Furthermore, lens 1102 can have a distance sensor (or any other sensor)that is located outside the eye and wirelessly coupled or directly wiredto power source 1110, as described above. The sensor can be a sensorcoupled to the lens 1102 (or any other suitable place on or adjacent theeye) or it can be located in the eye, and operate in substantially thesame manner as sensors described above.

Additionally, both lens 1002 and 1102 can have their respectiverefractive properties altered in any manner described herein and are notlimited the specific descriptions above. For example, lens 1102 and lens1002 can have their respective refractive properties altered by changingthe fluidic pressure as described above.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

1. A lens system comprising: a lens having at least one chamber housinga substance, said lens having a rigid wall and being configured to bepositioned externally and relative to an eye; a control unit operable tocontrol the exterior shape and focal length of said lens by adding fluidto or removing fluid from the chamber to change the pressure of thesubstance in the chamber so as to control of the shape and focal lengthof said lens to alter light rays passing through said lens, and focusthe light rays on the retina of the eye; and wherein the chamber is atleast partially enclosed by a flexible membrane, such that the lens iscapable of having the shape and focal length altered so as to be anegative diopter lens.
 2. The lens system of claim 1, wherein thecontrol unit is operable to receive a signal from a sensor, wherein whenthe signal is received, the signal includes information about acondition.
 3. The lens system of claim 2, wherein the condition is thedistance an object is from the lens.
 4. The lens system of claim 2,wherein the sensor is an integral part of the lens system and isconfigured to send automatic updates to the control unit such that theshape of the lens is continuously altered.
 5. The lens system of claim1, wherein said lens is a contact lens.
 6. The lens system of claim 1,wherein said lens is configured for use in spectacles.
 7. The lens ofclaim 1, wherein the control unit is operable to control the shape andfocal length of said lens by increasing the pressure of the substance inthe chamber.
 8. The lens of claim 1, wherein the control unit isoperable to control the shape and focal length of said lens bydecreasing the pressure of the substance in the chamber.
 9. The lenssystem of claim 1, wherein the chamber is enclosed by at least twoflexible members disposed opposite each other, such the lens is capableof having the shape and focal length altered so as to be a negativediopter lens.
 10. The lens system of claim 1, wherein the control unitis operable to receive manual input signals to control the exteriorshape and focal length of the lens.
 11. The lens system of claim 1,wherein the at least one chamber includes two chambers.
 12. A lenssystem comprising: a lens configured to be positioned external to theeye and including a flexible membrane and a rigid wall, the flexiblemembrane at least partially defining an exterior surface and thatdefines at least one interior chamber; a fluid contained within thechamber; a control unit configured to change the fluidic pressure in thechamber by adding fluid to or removing fluid from the chamber, so thatthe shape of the exterior surface of the lens is altered; wherein thechamber is at least partially enclosed by a flexible membrane, such thelens is capable of having the shape and focal length altered so as to bea negative diopter lens.
 13. The lens system of claim 12, wherein thecontrol unit is configured to increase the fluidic pressure in thechamber, so that the shape of the lens is altered.
 14. The lens systemof claim 12, wherein the control unit is configured to decrease thefluidic pressure in the chamber, so that the shape of the lens isaltered.
 15. The lens system of claim 12, wherein said lens isconfigured to be positioned at a location selected from the groupconsisting of on the external surface of the cornea and adjacent butspaced from the cornea.
 16. The lens system of claim 12, furthercomprising: a sensor, wherein said sensor is configured to sense acondition and said control unit is operable to receive a signal fromsaid sensor, and wherein when the condition is sensed and the signal isreceived, the signal includes information about the condition.
 17. Thelens system of claim 16, wherein said condition is the distance anobject is from the lens.
 18. The lens system of claim 17, wherein saiddistance is determined using a laser range finder.
 19. The lens systemof claim 16, wherein the condition is the distance of the object fromthe eye.
 20. The lens system of claim 12, wherein said lens isconfigured for use in spectacles.
 21. The lens system of claim 12,wherein the at least one interior chamber includes two interiorchambers.
 22. The lens system of claim 12, further comprising a sensorthat is an integral part of the lens system and is configured to sendautomatic updates to the control unit such that the shape of the lens iscontinuously altered.